Abstract: Project Background: People Living with HIV/AIDS smoke at nearly 3 times the rate of the general population. Although the majority of people living with HIV/AIDS are interested in receiving smoking cessation treatment, smoking cessation interventions may not be routinely offered in the HIV treatment setting. Recognizing these challenges, the Office of HIV, Hepatitis, and Public Health Pathogens Programs and the Tobacco & Health Policy and Program developed and recently disseminated the HIV Provider Smoking Cessation Handbook. Whether or not the dissemination of these materials has successfully lead to implementation efforts on the facility level is not known. Project Objectives: Responding to the both the major goal of the HIV/Hepatitis C QUERI's major goal to provide Better Chronic Disease Management for people living with HIV/AIDS as well as the SUD QUERI's major goal of addressing substance use as a complicating factor in the treatment HIV, the aim of this proposal is to use an explanatory mixed-method approach that is informed by the revised PARIHS framework to evaluate clinician-, facility-, and system-level barriers and facilitators associated with implementation of smoking cessation treatment within the HIV treatment setting. Projective Methods: To accomplish this aim we will recruit a purposive sample of clinicians from geographically diverse HIV treatment centers (n=8). Complementary quantitative and qualitative data sources will be used to triangulate findings and provide a full picture of mechanisms by which conceptual factors associated with the PARIHS framework (i.e., context, evidence, facilitation) are associated with implementation of smoking cessation evidence-based treatment. This method will allow us to use the PARIHS framework to diagnose and guide preliminary assessment of evidence and context and develop facilitation strategies based on existing evidence and local context. Anticipated Impacts of Veteran's Healthcare: This study addresses the VA mandate to provide smoking cessation interventions to all veterans who wish to quit smoking. It specifically addresses VA Office of Public Health concerns regarding how to best implement evidenced based smoking cessation interventions to the alarming number of patients with HIV who smoke. The results of this study will provide the foundation for our future plans to design, deploy, and evaluate targeted smoking cessation implementation efforts in HIV treatment settings.